Disposable mixing syringe

ABSTRACT

A disposable mixing syringe especially adapted for dental use is described. It comprises a barrel for receiving one component of a mixture to be formed and terminating in a flexible nozzle having a small orifice. The opposite barrel end is open and adapted to receive a sealed removable insert package constituted of puncturable material and containing a second component of the mixture to be formed. Inserting a mixing tool through the insert allows rapid mixing of the constituents, after which a suitable plunger is provided to expel the contents through the orifice.

United States Patent [1 1 Baskas Sept. 25, 1973 DISPOSABLE MIXING SYRINGE [75] lnventor: Morris J. Baskas, New Rochelle, Pnmary Examme': Rben Peshock Attorney-Jack Orsher 73 A 'ssignee Dentlpresslons Inc New York, N Y ABSTRACT [22] Flled: May 1972 A disposable mixing syringe especially adapted for den- [21] Appl. No.: 254,558 tal use is described. It comprises a barrel for receiving one component of a mixture to be formed and terminating in a flexible nozzle having a small orifice. The (5|. opposite barre] end is open and adapted to receive a [58] Fieid M 32/60 sealed removable insert package constituted of punc- 32/17 turable material and containing a second component of the mixture to be formed. Inserting a mixing tool through the insert allows rapid mixing of the constitu- [56] References cued ents, after which a suitable plunger is provided to expel UNITED STATES PATENTS the contents through the orifice. 2,754,590 7/1956 Cohen 32/60 2,869,543 1/1959 Ratcliff et al. 128/218 M 7 Claims, 4 Drawlng Flgul'es DISPOSABLE MIXING SYRINGE This invention relates to a combination mixing syringe and disposable dispensing device especially adapted for dental use for impression making.

Known dental impression techniques conventionally employ a tray filled with an impression material such as hydrocolloid which is pressed onto the patients jaw to form an impression of the teeth and gum. After hardening, the hydrocolloid is removed from the mouth and employed as a negative mold to form a positive casting by investing same with for example a suitable dental stone. This technique is cumbersome and has many disadvantages. It has been proposed to use a hardenable silicone in place of the hydrocolloid. However, to produce a hardenable silicone requires mixing of a basic silicone resin with a suitable catalyst. This is now accomplished by the dentist himself removing a suitable amount of the resin from a tube supplied by a supplier, adding to that a correct proportion of the catalyst also taken from a tube available from the supplier, mixing these ingredients on a suitable slab, transferring the mixing to a syringe, and then applying the mixture to the patients teeth. This procedure also is quite cumbersome and time-comsuming and requires the dentist to take the necessary precautions to ensure that the mixture is carefully proportioned and properly applied to the patient. Also, the syringe must then be cleansed for the next application.

The main object of theinvention is a device in which the correct proportions of a two-component mixture are pre-established though maintained separately, and by which they can be readily mixed, and the mixture then readily applied in an approporiate manner to an object to be coated, in particular, the teeth of a patient in a dental impression procedure.

This and other objects and advantages of the invention as will appear herein after are achieved, in accordance with the invention, by a disposable syringe having at one end a flexible or slightly flexible nozzle having a tiny orifice through which the mixture may be expelled and containing the larger of the two components to be mixed. The smaller of the two components is separately packaged in a puncturable skin configured as a removable insert to seat within the opposite end of the syringe.

In use the operator employs a suitable tool, such as a spatula, to puncture through the enclosing skin of the insert allowing the smaller component to come into contact with the larger component, and can then use the same puncturing tool to thoughly mix together the two components. Then, the punctured insert is removed and discarded, and a suitable plunger inserted in the open end to expel the mixture through the tiny orifice.

A feature of the invention is the use of a syringe configured to be usable with an air valve and an airpressure-applying device enabling very uniform extrusion of the mixture from the orifice. When the mixture is a hardenable silicone, this enables the dentist to spread a thin film of the silicone mixture evenly over the patients tooth structure forming, when hardened, a very accurate detailed impression thereof.

A further feature is a removable packaged insert for the smaller component constructed of heat-sealable foil, which is inexpensive to manufacture, easily punctured, and allows the printing of suitable instructions for the dentist.

Among the advantages of the novel device of the invention are low-cost manufacture, pre-measured proportions of the ingredients ensuring the optimum mixture composition, disposability due to low cost, minimum time expenditure by the dentist, and the achievement of excellent impressions.

One exemplary embodiment of, the invention will now be described in greater detail with reference to the accompanying drawing, wherein:

FIG. 1 is an exploded elevational view of the various parts of one form of combination-syringe and mixing device of the invention;

FIG. 2 is a top view of the insert package;

FIG. 3 is a cross-section of the syringe showing how it is used;

FIG. 4 is a side view of the syringe fitted with means for pressure dispensing of the mixture.

One form of the invention is shown in exploded view for clarity in FIG. 1. It comprises a disposable syringe 5 comprising a generally cylindrical barrel l0 tapering downatits bottom end to a flexible nozzle 11 having a tiny orifice 12.

It may be constituted of any suitable plastic resin. The upper end is formed with an enlarged flange 13 by which the syringe may by manually held or secured to a pressure-generating device. The top surface 15 of the flange is generally flat. The nozzle end 1 1 can be closed off with a removal cap 16 which may be held on the nozzle by a friction fit. The barrel l0 accommodates the first, larger component of the mixture to be formed, shown in 17 in FIG. 3.

The second, smaller component of the mixture to be formed, designated 18 in FIG. 3, is separately packaged in a removable sealed insert 20, comprising a flanged portion 21 adapted to be seated on the top 15 of the flange 13 of the barrel, and which has depending therefrom a bubble portion 22 with an annular ridge as shown containing the second component. The insert is preferably constituted of a puncturable plastic foil or sheet 23, for example of styrene, shaped, for example by vacuum-forming, to form the bubble or cup with an overlapping puncturable sheet 24 of for example aluminum which can be heat-sealed with a suitable adhesive to the plastic where the sheets are incontact. If desired, appropriate instructions for the dentist can be imprinted on the top sheet. Top sheet 24 can also be of paper-backed aluminum.

The barrel 10 would be filed with the first component 17 by the laboratory supplier with the cap 16 in place to prevent loss through the orifice. The second component 18 is provided within the bubble 22 and the overlying sheet 24 sealed in place to completely enclose the second component and maintain it completelyseparated from the first component. Then the insert 20 is positioned in the upper open end 25' of the barrel and the combination sealed in a envelope, or the insert held in place by plastic tape or by sealing a conventional stretch material around the top.

In use, after the patient has been prepared for taking of the impression, the dentist removes the stretch material or envelope, and merely inserts a spatula 30 or like paddle type of tool as shown in FIG. 3 through the insert 20 into the barrel. This causes puncturing of the top 24 and bottom 23 sheets allowing the second component l8, usually a liquid, to flow. into the barrel and come into contact therein with the first component 17. The dentist then manipulates the spatula 30 to thoroughly mix the two components. For this purpose, the tool may have a cylindrical shank which can be inserted into a conventional handpiece to power rotate the tool allowing rapid mixing of the two constituents. This need only take some lO2O seconds. Next, the dentist removes the mixing tool 30 and then removes the punctured insert package 20 using the flanged portion as a gripping means, which can be discarded.

To expel the mixture, a suitable plunger 32 of elastic material is then inserted in the open end 25, and after removal of the cap 16, pressing of the plunger will expel the mixture in a uniform bead from the orifice 12. In this way, the dentist can apply a thin coating of a silicone mixture over the patients tooth and gum structure to form the desired mold or impression thereof. Afterwards, the syringe 5 may be disposed of. A heavy bodied supporting material is then conventionally applied over the thin silicone coating.

FIG. 2 is a top view of the insert 20 showing the general outline thereof. THe barrel flange 13 will have a similar configuration.

For more uniform mixture dispensing, a pressurized air system can be coupled to the syringe. This is illustrated in FIG. 4. After the mixture has been formed and the mixing tool and insert removed, a shankless plunger 35 is inserted in the barrel open end, and then a suitable air-valve 36 attached to the open end of the barrel using its flange 13 to hold the air-valve in place. A supply of pressurized air is coupled by way of a suitable conduit 37 to the air-valve. On pressing the air-valve actuator 38, air under controlled pressure pushes the plunger 35 uniformly into the barrel expelling the mixture from the orifice.

As has been briefly mentioned above, the invention is generally applicable to any two-component mixture which requires component separation up until the moment of use, and then intimate contact of the components in preferred proportions in a device enabling rapid and controlled dispensing where desired. Typically, the components will be of the type that undergo a chemical reaction when brought into contact with one another. In the dental field, generally the components will form plastic resin compositions, frequently involving a change of form or state. Thus, both components may be liquids, which when contacted harden to form a solid. As mentioned, an important class of materials for dental use is the so-called silicone resins, of the fast-setting type, which requires mixing ofa resin component and catalyst hardener. A reaction occurs immediately causing setting in some cases in as short as 3 minutes. Thus, the mixed resin has to be applied quickly. Anyof the commercially available silicones, which are primarily organosilicon compositions, can be used. They are available from suppliers such as DOW- CORNING as a component system comprising a resin and a catalyst. The catalyst when added causes polymerisation of the resin both linearly or by crosslinking converting the liquid resin into a solid. For making dental impressions, the silicone used forms a firm, flexible or rubbery material that, after removal from the patients mouth can be used as a mold in which suitable materials can be cast, such as dental stone, to form a positive duplicate or master cast of the patients mouth to serve as a base in dental restoration for making various dental parts, such as inlays, crowns, bridges, dentures, and the like. To obtain a model of the upper and lower jaws of the patient, generally an impression of each jaw is taken separately. The invention is especially useful for this application because the syringe can be prepacked with a prc-measured quantity of material as required for one-half of a typical patient's mouth. Thus, using a conventional dental silicone for this purpose, the syringe should have a capacity to receive about 4 cc of the liquid resin and the insert should have a volume to receive about 1 cc of the catalyst. The conventional silicone impression material in these proportions would harden in about 3 minutes. Preferably, the catalyst is colored differently than the resin, which will aid the dentist in determining by observation of the color uniformity of the syringe contents whether sufficient mixing has been effected.

While the principles of the invention have now been made clear in several illustrative embodiments, there will be immediately obvious to those skilled in the art many modifications in structure, arrangement proportions, the elements, materials, and components, used in the practice of the invention, and otherwise, which are particularly adapted for specific environments and operating requirements, without departing from those principles. The appended claims are therefore intended to cover and embrace any such modifications, within the limits only of the true spirit and scope of the invention.

What is claimed is:

l. A disposable syringe and mixing assembly comprising an elongated syringe barrel having an exiting orifice at one end and an opening at the opposite end, a first component of a mixture to be formed located directly within the syringe barrel in contact with the walls thereof, a relatively small permanently sealed insert package wholly of puncturable thin foil sheet material, a second component of the mixture to be formed located and sealed within the insert package, means including a flanged portion on the insert package and a portion depending from the flanged portion and seated within the opening at the opposite end of the syringe barrel for removably mounting the insert package thereat, said insert package being puncturable by a mixing spatula allowing mixing of the first and second components and removal of the empty package by using the flanged portion as a gripping means, and plunger'means separable from the insert package and having a diameter large enough to engage the barrel walls for insertion in the syringe for expelling the mixture through the exiting orifice.

2. A disposable syringe and mixing assembly as claimed in claim 1 wherein the exiting orifice is small and the opposite end opening is larger.

3. A syringe and mixing assembly as claimed in claim 2 wherein the opposite end of the barrel has a flange, and the insert flange adapted to seat on the barrel flange.

4. A syringe and mixing assembly as set forth in claim 3 wherein the insert portion which depends from the flange and seats within the barrel opening has the shape of a bubble.

5. A syringe and mixing assembly as set forth in claim 4 wherein the insert comprises two sheets of puncturable material heat-sealed at their flanges.

6. A syringe and mixing assembly as set forth in claim 5 wherein the bubble portion of the insert has a relatively small height compared with the overall height of the syringe barrel.

7. A disposable syringe and mixing assembly as claimed in claim 1 wherein the first and second components are both liquids having colors that differ from one another. 

1. A disposable syringe and mixing assembly comprising an elongated syringe barrel having an exiting orifice at one end and an opening at the opposite end, a first component of a mixture to be formed located directly within the syringe barrel in contact with the walls thereof, a relatively small permanently sealed insert package wholly of puncturable thin foil sheet material, a second component of the mixture to be formed located and sealed within the insert package, means including a flanged portion on the insert package and a portion depending from the flanged portion and seated within the opening at the opposite end of the syringe barrel for removably mounting the insert package thereat, said insert package being puncturable by a mixing spatula allowing mixing of the first and second components and removal of the empty package by using the flanged portion as a gripping means, and plunger means separable from the insert package and having a diameter large enough to engage the barrel walls for insertion in the syringe for expelling the mixture through the exiting orifice.
 2. A disposable syringe and mixing assembly as claimed in claim 1 wherein the exiting orifice is small and the opposite end opening is larger.
 3. A syringe and mixing assembly as claimed in claim 2 wherein the opposite end of the barrel has a flange, and the insert flange adapted to seat on the barrel flange.
 4. A syringe and mixing assembly as set forth in claim 3 wherein the insert portion which depends from the flange and seats within the barrel opening has the shape of a bubble.
 5. A syringe and mixing assembly as set forth in claim 4 wherein the insert comprises two sheets of puncturable material heat-sealed at their flanges.
 6. A syringe and mixing assembly as set forth in claim 5 wherein the bubble portion of the insert has a relatively small height compared with the overall height of the syringe barrel.
 7. A disposable syringe and mixing assembly as claimed in claim 1 wherein the first and second components are both liquids having colors that differ from one another. 